Is it permissible for the creditor and the debtor to agree on settling a specific debt (a sum of money) with a certain weight of a commodity (iron) instead of the cash amount, with a delivery date specified?

It is permissible for the creditor to take something other than the type of his debt when it becomes due. However, it is not permissible to take a commodity described in the liability in exchange for the debt, due to the annulment of the debt in a specific item whose possession is delayed, whether the commodity is of the same type as the debt or not.